METHOD OF FORMING GATE STACK AND STRUCTURE THEREOF

摘要

Embodiments of the present invention provide a method of forming gate stacks for field-effect-transistors. The method includes forming a metal-containing layer directly on a first titanium-nitride (TiN) layer, the first TiN layer covering areas of a semiconductor substrate designated for first and second types of field-effect-transistors; forming a capping layer of a second TiN layer on top of the metal-containing layer; patterning the second TiN layer and the metal-containing layer to cover only a first portion of the first TiN layer, the first portion of the first TiN layer covering an area designated for the first type of field-effect-transistors; etching away a second portion of the first TiN layer exposed by the patterning while protecting the first portion of the first TiN layer, from the etching, through covering with at least a portion of thickness of the patterned metal-containing layer; and forming a third TiN layer covering an areas of the semiconductor substrate designated for the second type of field-effect-transistors.